Cybaeus tardatus, Chamberlin, 1924

Bennett, Robb, Copley, Claudia & Copley, Darren, 2021, Cybaeus (Araneae: Cybaeidae) in the Nearctic: the devius and tardatus species groups of the Californian clade, Zootaxa 5026 (4), pp. 451-479 : 464

The tardatus species group

Diagnosis. The tardatus group is diagnosed by the somewhat triangular form of the vulva and the simple, longitudinally elongated, centrally located copulatory ducts ( Figs 34–35, 37–38 , 42–43, 45 , 50–51 ).

Description. Medium- to large-sized spiders: carapace lengths averaging 2.6–3.1 mm (females). Males subequal. Abdomen patterned. Femora and tibiae banded or not. Two or three complete pairs of ventral tibia I macrosetae; distal pair present, absent, or incomplete.

Male: Patellar apophysis ( Figs 39 , 47 , 56 ) about as long as tibial width, anteriorly directed, about 25–40 peg setae. Retrolateral tibial apophysis carinate, nearly as long as tibia or slightly truncated anteriorly. Embolus ( Figs 40 , 48 ) long, thin. Distal and proximal arms of tegular apophysis species specific ( Figs 40–41 , 48–49 , 57–61 ): distal arm elongated or short, proximal arm with bifid tip.

Female: Atrium ( Figs 33, 36 , 44 , 50 ) with paired longitudinal atrial openings, atrium hooded anteriorly ( Fig. 52 ) or not. Copulatory ducts ( Figs 35, 38 , 43, 45 , 51, 54 ) long, relatively simple, contiguous or separated. Spermathecal heads simple, small lobes or undifferentiated from rest of vulval ducts. Spermathecal stalks simple, of variable length. Spermathecal bases rounded or elongated. Bennett’s glands located on surface of bases near junction with stalks.

Composition and distribution. ( Fig. 62 ). Cybaeus orarius Bennett spec. nov., C. piazzai Bennett spec. nov., C. tardatus (Chamberlin) , and C. topanga Bennett spec. nov. All four species are rarely encountered and have small ranges scattered along the southern coast of western California from southern Monterey County south to the Mexican border.

Figures

FIGURE 62. Distribution of Cybaeus orarius spec. nov., C. piazzai spec. nov., C. tardatus, and C. topanga spec. nov. AZ— Arizona, CA—California, ID—Idaho, OR—Oregon, NV—Nevada, UT—Utah, WA—Washington. California county names capitalized.

FIGURES 33–38. Cybaeus orarius spec. nov., females from California, copulatory organ (33–35 from Big Sur Highway, 36–38 from Cambria). 33, 36 Epigynum, ventral. 34–35, 37–38 Vulva (34, 37 ventral, 35, 38 dorsal). BG—Bennett’s gland, CD—copulatory duct, HS—head of spermatheca, SS—stalk of spermatheca.

FIGURES 42–45. Cybaeus piazzai spec. nov., females from California, copulatory organ (42–43 from Santa Barbara Natural History Museum grounds, 44–45 from “W119/N34”). 42–43 Vulva, ventral. 44 Epigynum, ventral. 45 Vulva, dorsal). CD— copulatory duct.

FIGURES 50–54. Cybaeus spp., females, copulatory organ (50–51 C. tardatus, holotype of Namopsilus pletus; 52–54 C. topanga spec. nov., from San Ysidro, California). 50–51, 53–54 Vulva (50, 53 ventral, 51, 54 dorsal). 52 Atrium (anterior portion), ventral. BG—Bennett’s gland, CD—copulatory duct, SS—stalk of spermatheca.

FIGURES 39–41. Cybaeus piazzai spec. nov., male from Santa Barbara, California, left palpus. 39 Patella and tibia, dorsal. 40–41 Genital bulb (40 ventral, 41 retrolateral). CY—cymbium, DA—distal arm of tegular apophysis, E—embolus, PA— proximal arm of tegular apophysis, RTA—retrolateral tibial apophysis. Unlabelled arrow indicates concave distal prolateral margin of DA.

FIGURES 46–49. Cybaeus tardatus, male from Claremont, California, left palpus. 46–47 Patella and tibia (46 retrolateral, 47 dorsal). 48–49 Genital bulb (48 ventral, 49 retrolateral). DA—distal arm of tegular apophysis, E—embolus, PA—proximal arm of tegular apophysis, PTA—patellar apophysis, RTA—retrolateral tibial apophysis.

FIGURES 55–58. Cybaeus topanga spec. nov., holotype male, left palpus. 55–56 Patella and tibia (55 retrolateral, 56 dorsal). 57–58 Genital bulb (57 ventral, 58 retrolateral).E—embolus, PA—proximal arm of tegular apophysis, PTA—patellar apophysis, RTA—retrolateral tibial apophysis. Unlabelled arrow indicates concave distal prolateral margin of DA.